1. Field of the Invention
This invention lies in the field of apparatus for facilitating the construction of long cylindrical vessels. More particularly it concerns apparatus for facilitating the process of welding two or more relatively short cylinders of rolled steel plate, of substantially the same diameter, that may not be perfectly circular.
2. Description of the Prior Art
In the prior art, it has been customary to weld a plurality of short cylinders in butt welding in coaxial position so as to construct and fabricate long cylindrical vessels.
However, the process of welding two cylinders into a single long structure is quite difficult. For example, if the cylinders rolled are say 10 feet in diameter and 10 feet long, a reasonably perfect cylinder rarely emerges from the rolls, and the cylinders as rolled are typically "oval" to a greater or lesser degree. If the metal thickness is 1/2 inch and if the ovalling causes the cylinder diameter to be say 3 inches greater at one point that at another it is impossible to mate the 1/2 inch metal thicknesses in preparation for welding them together at the point of abutment. The normal procedure has been to apply impulsive forces by sledge hammer or otherwise to force an oval cylinder into a circular cylinder, but this is very time consuming and difficult to control.